Some communication systems allow the user of a device, such as a personal computer, to communicate across a packet-based computer network such as the Internet. Such communication systems include voice over internet protocol (“VoIP”) communication systems. These systems are beneficial to the user as they are often of significantly lower cost than conventional fixed line or mobile networks. This may particularly be the case for long-distance communication. To use a VoIP system, the user installs and executes client software on their device. The client software provides the VoIP connections as well as other functions such as registration and authentication. In addition to voice communication, the client may also provide further features such as video calling, instant messaging (“IM”), SMS messaging, file transfer and voicemail.
One type of communication system for packet-based communication uses a peer-to-peer (“P2P”) topology. To enable access to a peer-to-peer system, a user must execute P2P client software provided by a P2P software provider on their terminal, and register with the P2P system. When the user registers with the P2P system, the client software is provided with a digital certificate from a server. Once the client software has been provided with the certificate, then calls or other communications can subsequently be set up and routed between users of the P2P system without the further use of a server in the set-up. Instead, the client looks up the required IP addresses from information distributed amongst the P2P client software on other end users' terminals within the P2P system. Once the IP address of a callee's terminal has thus been determined, the caller's P2P client software then exchanges certificates with the callee's P2P client software. The exchange of the digital certificates (or user identity certificates, “UIC”) between users provides proof of the users' identities and that they are suitably authorised and authenticated in the P2P system. Therefore, the presentation of digital certificates provides trust in the identity of the users.
It is therefore a characteristic of peer-to-peer communication that, once registered, the users can set up their own communication routes through the P2P system in a decentralized manner based on distributed address look-up and the exchange of one or more digital certificates, without using a server for those purposes. Further details on such a P2P system are disclosed in WO 2005/008524 and WO 2005/009019.
VoIP or other packet-based communications can also be implemented using non-P2P systems that do use centralized call set-up.
A problem with packet-based communication systems is that a reliable connection with a sufficient bandwidth is required to the Internet or other packet-based network. Whilst this is generally not a problem when the user is at a known, fixed location (such as their home), establishing a connection can be problematic when the user is travelling and must access the packet-based network via a wireless access node of unknown quality. For example, wireless Internet hotspots, provided by wireless local area network (“WLAN”) access points and appropriate hotspot software, are widely available for use by users when travelling. These are often available in public areas such as airports, cafes and stations, and are operated by a third-party service provider other than the provider of the client software. However, these hotspots are often not freely usable to anyone, and instead access to Internet is restricted and secured. The hotspots require the user to obtain login credentials from the hotspot operator, e.g. in return for payment.
For instance, a protocol such as the Wireless Internet Service Provider roaming (“WISPr”) protocol can be used for accessing the hotspot. When the WISPr protocol is used, a user attempting to connect to the internet using a restricted-access hotspot is redirected to a login server of the operator of the hotspot. This redirection results in the display of a login page to the user. The login page prompts the user to either enter a username and password (for example if this has been purchased in advance by the user or provided as part of a pre-arranged billing arrangement) or enter credit card (or other payment) details. By entering the required information the user gains access to the hotspot and can connect to the Internet, and if required is charged accordingly. Alternatively, smart clients can be used that automate the login process based on the WISPr information contained in the login page. Smart clients may hide the complexity of login process from end user. For example, Skype Access is one such smart client.